Its not working very good.
Save money, buy a good used M7, turbo it.
They are insane how well they work.
Or if interested I know of one already done up nicely, and he is selling it.
The M8 for some reason is not working to well this season, the M7 and M1000 both seem to work incredibly well with a little set up, but i have yet to see an M8 that impresses me.
Just my observations is all.
As I am sure somewhere, someone has an M8 dialed in perfectly, and it rocks.